The pace of life is forever speeding up. Technological breakthroughs spread through society in years rather than centuries. Calculations that would have taken decades are now made in minutes. Communication that used to take months happens in seconds. In almost every area of life, change is occurring faster and faster.

Yet, this acceleration is not confined to modern times. Medieval architecture and agriculture, for instance, varied very little over the period of a century. But even then change occurred much faster than it did in prehistoric times. Stone Age tools remained unchanged for thousands of years.